^{page 105 of note *} References are to pages in the undermentioned works, and are abbreviated as follows : B. : Boole, G. Differential Equatzons, 4th ed. (1877).Google Scholar FI : Forsgth, A.R., Treatise on Differential Eqzirttzons, 6th ed. (1929).Google Scholar I .: Forsvth, A.R.. Theory of Differential Enuatlons. Part I (1890).Google Scholar G. : Goursag Cows, E. l. 11, 4th ed. (1925).Google Scholar I. : Ince, E.L., Ordinary Dzfferentinl Equations (1927).Google Scholar P : Piaggio, H.T.H., Treatise on Differential Equations, revised ed. (1825).Google Scholar W : Wilson, E.B., Advanced Calculus (1911).Google Scholar

^{page 108 of note *} See also the footnote to section VI.

^{page 109 of note *} Though not usually desirable as a practical method of integration, after λ has been found, instead of proceeding to the final integration, this method may be used in conjunction with method IV Thus, if µ and µ, have the values given in IV (ii). the above integral may be written in either of the forms